47
Model 4688-IR / Model 4679-IR
Operation & Maintenance Manual
Manual #087-0007G, 10/2003
Displayed
As:
Description
Min
Max
Default
Value
MEM
Region
MODBUS
Register
Address
Data
Type
[BITS]
Assigned
Parameter
#
SR.dC
Sensor Damping Constant
- Specifies the damping time
constant in seconds. This is the amount of time that it will
take the unit to reach 63% of its final value when suddenly
exposed to a known concentration of gas. The time to
reach 95% of final value may be estimated by multiplying
this setting by 3. This period is only valid for an immersion
test without membrane filters and does not include the time
required to transport the gas or fill the sensor chamber.
Note that the lower the damping time constant, the more
unstable the reading will be.
0 s
2 s
2 s
PMEM
40337
[hi byte]
Unsigned
Byte
[8]
26
SR.dP
Sensor Decimal Precision
- Specifies the maximum
precision of the displayed concentration.
0=No Decimal Point
1=0.1
2=0.01
3=0.001
0
3
0 (No
Decimal
Point)
PMEM
40337
[low byte]
Unsigned
Byte
[8]
27
1
100
100
CO
2
0.00% v/v
5% v/v
5(% v/v)
SR.GN
Sensor Gas Number
- Specifies the particular
hydrocarbon gas for which the transmitter will produce a
reading and output signal which is linear to the measured
concentration.
NOTE
:
changing this parameter RESETS
the alarm setpoints and reset points, the negative drift limit,
the display units, and decimal precision parameters. See
the parameter description for default values.
1. Methane 15. Methanol*
2. Ethane 16. Butadiene*
3. Propane 17. Pure Methane*
4. Butane 18. 20% V/V Hexane*
5. Pentane 19. Ethanol*
6. Hexane 20. Benzene
9. Ethylene* 21. Xylene
10. Propylene 22. Isobutanol Isobuty
11. Acetone* Alcohol
12 . IPA* 23. Rotosolv-1
13. MEK* 24. Cyclohexane
14. Toluene* 64. Carbon Dioxide **
*Only the "extended" gas(es) specifically ordered can be
selected. "Extended" gases are only included in transmitters
ordered with this option and are not found in units equipped
with only the "standard" gas set.
**The Carbon Dioxide (SR.GN-64) setting is available.
1
6
1
(Methane)
PMEM
40335
Unsigned
Byte
[8]
29
SR.tP
Sensor Temperature (Read Only)
- This is the
temperature in either °F or °C, according to the value
current set by SR.tU (below).
-99.0°F
500°F
Current
VMEM
40405
REAL
[32]
30
SR.FS
Sensor Full Scale (Read Only)
- This value represents the
concentration level (in %LEL or %V/V) corresponding to 20
mA on the 4-20 mA current loop output. It is assigned
according to gas selection and displayed engineering units.
When displaying the measured concentration in %LEL, the
value is always 100. When measuring the concentration in
units of %V/V, the value is the % mix of gas to air (at STP)
known as the Lower Explosive Limit (or Lower Flammable
Limit).
PMEM
40329
USER MENU - Sensor Parameters
(continued…)
REAL
[32]
28
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
